With the retail of DVD-ROMs and BD-ROMs, the greater the number of variations of a movie work (title) that can be sold on a single disk, the greater the added value of the product. Scenario data called static scenarios and dynamic scenarios plays a positive role in increasing the number of title variations. A static scenario is information showing a playback path defined in advance by a disk creator. In comparison, a dynamic scenario is a scenario that dynamically changes the progress of playback according to a status setting of the device.
FIGS. 1A-1C show a dynamic scenario. The dynamic scenario realizes a “language credit” for switching playback scenes according to a language setting in the playback device. In FIGS. 1A-1C, “PL” is short for PlayList, which is a playback path, and “PI” is short for PlayItem, which is a playback section. The dynamic scenario in FIGS. 1A-1C realizes conditional playback such that if the language setting (SPRM(0)) in the playback device is “Japanese” (i.e. “if(SPRM(0))=Japanese”), playback section PI#1 of playback path PL#4 (PL#4, PI#1) is played, and if the language setting in the playback device is other than PL#4 (i.e. “else”), playback section PI#1 of playback path PL#2 (PL#2, PI#1) is played. As a result of this conditional playback, playback is performed via playback paths that differ depending on the language setting made by the user. The arrows hb1 and hb2 in FIG. 1B symbolically show the conditional branching that results from a dynamic scenario. The prior art relating to DVD playback controls includes the known technology disclosed in Japanese patent application no. 2856363.
However, if the user conducts a menu call while the playback device is executing a playback control in accordance with an internal status setting, there is a danger that the status setting of the playback device will be altered. A menu call is an on-demand type branch for branching to a status-setting routine in the playback device triggered by the user depressing a menu key. Being a call rather than a jump, the menu call follows processing (1) for saving a value held in a register of the playback device prior to the execution of the status-setting routine, and follows processing (2) for restoring the saved value to the register after the execution of the status-setting routine. Register-held values that are saved and restored show the current point in time of playback. As such, even if the user requests a menu call in the middle of a playback path, thereby initiating a status-setting routine, playback is resumed from immediately after the previous playback position once the status-setting routine has ended.
In the example given here, the language setting in the playback device is English, and the playback time in FIGS. 1A-1C is over PL#2, which is the playback path specifically for English. If a menu call is conducted in the above state and the status setting in the playback device is updated from English to Japanese, the playback device loses the position for resuming playback. This is because it does not make sense to resume playback on the English language playback path when the language setting has changed from English to Japanese as a result of the menu call. Also, the setting of a meaningless playback position risks inviting a hang up when software is implemented in the playback device.
These difficulties can be avoided by uniformly prohibiting menu calls. However, when a number of versions of a movie work are recorded on a single optical disk, it is fully conceivable that a title that does not execute language credits is recorded on the optical disk. Uniformly preventing menu calls during the playback of titles shows a lack of consideration to the user.
An object of the present invention is to provide a recording medium capable of executing menu calls in response to the particular characteristics of individual titles when different versions of a movie work are recorded on a single recording medium.